Detent for selector switches



June 13, 1950 G. H. KLAY 2,511,349

DETENT FOR SELECTOR SWITCHES Filed Oct. 30, 1948 I VII/1,1111! I} A I l *Nl ll"...

ATTORNEYS Patented June 13, 1950 DETENT FOR SELECTOR SWITCHES George H. Klay, Blufiton, Ohio, assignor to The Triplett Electrical Instrument Co., Bluffton, Ohio, a corporation of Ohio Application October 30, 1948, SerialNo. 57,553

v This invention relates to indexing devices, and particularly to sucha device adapted for use in connection with electric snap switches, such as rotary selector switches.

In connection with selector switches, it is important that the switches be indexed accurately to position and that the indexing mechanism have long life and still permit relatively easy turning of the switch.

It has been customary to provide such switches with an indexing plate having recesses or notches therein and which are engaged by detent means for determining the several positions of the switch.

The detent means ordinarily take the form of spring pressed balls, spring pressed plungers, or springs of such a shape that they will engage the detent recesses themselves.

Each of these arrangements is somewhat dissatisfactory, because in the case of the balls or plungers, it is necessary to provide them with a relatively stilf spring and to provide a bore or other restraining means for retaining them in position. The life of such detent mechanisms is ordinarily not very long, and either do not provide proper positioning of the index plate or else 'the indexing of the plate is diflicult.-

In connection with the aforementioned spring arrangement it is necessary to provide a firm anchor for the spring and this is sometimes difiicult to accomplish.

The object of the present invention is to provide an improved indexing device for rotary selector switches and the like which overcomes the difficulties referred to above.

Another object of the invention is the provision of an indexing mechanism adapted for selector switches and the like which has long life.

It is also an object to provide an indexing mechanism in which the mechanism can readily be adjusted from one position to another.

It is also an object of this invention to provide an indexing arrangement for selector switches and the like in which the said indexing mechanism occupies a, very small amount of space.

These and other objects and advantages will become apparent from the following description taken in connection with the accompanying drawings wherein:

Figure 1 is a perspective view showing a portion of a switch constructed according to this invention;

Figure 2 is a vertical section through the switch indicated by the line 22 on Figure 1;

3 Claims. (Cl. 74-527) Figure 3 is a vertical section indicated by the 2 line 3-3 on Figure 2 and looking in at the indexing mechanism proper; and

Figure 4 is a fragmentary view indicated by the line 44 on Figure 3.

Referring to the drawings somewhat more in detail, the arrangement shown therein is an indexing device for a rotary snap action selector switch, and which may be of the type illustrated in myco-pending application, Serial No. 5,217, filed January 30, 1948, and assigned to the same assignee as the instant application.

The arrangement shown comprises a body part II] which is preferably of electrical insulating material, so that it can form a part of the body of the switch to be actuated by the indexing device.

The body I!) has a cylindrical recess [2 therein and within this recess there is disposed a peripherally notched plate 14. It will be noted, on reference to Figure 2, that the recess and the plate are relatively thin in the axial direction.

The recess I2 is closed by a cover member l6 and the cover member I6 is retained in position on the body l0 as by the bolts l8.

Extending axially through the plate It and body It is a shaft 211 and on which the index plate I4 is rigidly mounted as by brazing.

The shaft 20 is adapted for receiving an actuator knob 22 at the front of the indexing device and has a blade 24 extending out the other side of the indexing device for engagement with the switch or other device to be actuated.

Turning to Figure 3, it will be noted that the notched plate I4 is substantially smaller in diameter than the recess 12 so that there is an annular space extending completely around the said plate.

In this space there are a pair of curved arms 26, each of which has on its inner side an arcuate projection 28 that engages one of the notches in the periphery of the plate.

As will be seen these projections preferably engage notches substantially diametrically opposite on the .plate and this is of value because it provides for balanced loading on the plate and substantially eliminates radial thrusts during the indexing operation.

Each of the arms '26 has an eye formed in one end thereof and these eyes fit over studs or lugs 39 which are upstanding from the bottom wall of the recess 12 and at one side of the plate M. The other ends of the arms are connected by a tension spring 32 and it will be noted that this spring is relatively long and thus is adapted for long life and also retains substantially the same pressure on the arms 26 at all timefiq In operation, the shaft 20 is caused to rotate for indexing the switch or other device to which the indexing mechanism is connected by grasping the knob 20 and turning it. Through its connection with the shaft by means of the set screw 34, rotation of the knob turns the shaft and thereby also turns the notched plate l4. As this plate 14 turns the arcuate projections 28 on the arms 26 are cammed out of the notches in which they rest. Continued rotation of the [plate will bring another pair of notches beneath the said projections and the spring 32 will cause said projections to be snapped into the said slots.

It will be apparent that indexing of the device is relatively easy at all times, but that the positioning thereof by the engagement of the notches by the projections 28 is quite accurate. There is little wear on the lugs or studs 3|] and there is not sufficient resilience on the arms 26 to vary the distance of the projections 28 from the said lugs.

While the device of this invention has been shown as constructed partly of metal and partly of insulating material, it will be understood that it could be made entirely from either oneof these materials, if so desired.

Furthermore, the lugs or studs 30 have been shown as upstanding from the body part l0, and this is of advantage because they may be molded directly thereon when the said body is formed. But, it will be understood that other means could be provided for pivoting the arms, such as pivot means upstanding from the plate I6, or studs of metal inserted into the body [0 at the positions occupied by the studs 30.

It will be understood that this invention is susceptible to modification in order to adopt it to different usages and conditions and, accordingly, it is desired to comprehend such modifications within this invention as may fall within the scope of the appended claims.

I claim:

1. In an indexing device for selector switches and the like; a body part having a circular recess, an ctuatingshaft for the switch extending axially through said recess, a circular plate having spaced peripheral notches attached to said shaft in said recess and forming an annular cavity with said recess, a pair of arcuate arms in said annular cavity pivoted to said body at one of their ends at one side of said plate and resiliently urged toward each other at their other ends at the otherside of said plate, and arcuate projections on the inside of said arms engaging notches in said plate, said arms being of substantially the same thickness as said plate.

2. In an indexing device for selector switches and the like, a body part having a circular recess, an actuating shaft for the switch extending axially through said recess, a circular plate having uniformly spaced peripheral notches and attached to said shaft in said recess and forming an annular cavity with said recess, a pair of arcuate arms in said recess lying about the periphcry of said plate, means upstanding from the bottom wall of said cavity at one side of said plate for pivotally supporting said arms on said body at one end, resilient means connecting said arms at the other end and extending directly between the other ends of the arms in said cavity at the other side of said plate and arcuate projections on the inside of said arms intermediate their ends and extending into notches in said plate, said projections engaging said plate at substantially diametrically opposite points, said plate, arms, and resilient means being of substantially the same thickness.

3. In an indexing device for selector switches or the like, a body part having a cylindrical recess in one side, a cover member closing said recess, a shaft axially traversing said recess, a circular vplate on said shaft in said recess having uniformly spaced peripheral notches and forming an annular cavity with said recess, pivot means in said recess at one side of said plate comprising studs upstanding from the bottom Wall of said cavity, a pair of arms fitting over said studs to be pivoted thereon and curving around opposite sides of said plate, a tension spring extending directly between the free ends of said arms on the other side of said plate in said cavity, and arcuate projections on the inside of said arms extending into the notches in said plate, said projections engaging said plate at diametrically opposite points, said plate, arms, and spring being substantially equal to each other and to the depth of said recess in thickness.

GEORGE I-I. KLAY.

R ERE E CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,538,438 Bliss June 15, 1926 2,115,284 Pratt Apr. 26, 1938 2,195,251 Kimball Mar. 26, 1940 2,359,661 Moody Oct. 3, 1944 2,436,750 Gray Feb. 24, 1943 

